This analysis showed that DCIS lesions expressing higher numbers of nuclear BCL9-positive cells were more likely to be ER-negative (p = 0.004; Wilcoxon rank sum test), PR-negative (p = 0.003; Wilcoxon rank-sum test), high nuclear grade (Spearman correlation = 0.49; p = 0.008), and high HER2-expressing (Spearman correlation = 0.56; p = 0.002; Fig. 10c). Here, ESR1 is linked to ductal breast carcinoma in situ.